From: filip.hrbek at plz.comstar.cz (Filip Hrbek)
Date: Mon, 23 Oct 2006 10:02:42 +0200
Subject: [Pljava-dev] Cancelling trigger operation
References: <449f4cf70610180438x3c928febw693667dae457e841@mail.gmail.com>
	<45367CD0.8090202@tada.se>
Message-ID: <003601c6f679$9e1af3c0$1e03a8c0@fhrbek>

Hi Thomas,

when a trigger function is written in pl/pgsql, you can decide to cancel the 
operation in a trigger(defined as "before event") by returning null instead 
of "new", e.g.

create function cancelling_trigger() returns trigger as
'
begin
  if new.num < 0 then
    -- cancel operation for negative numbers
    return null;
  else
    -- continue
    -- do something...
    return new;
  end if;
end
' language 'plpgsql';

Is there any way to do the same in pljava? I can't see it now, since the 
trigger functions are mapped to static java methods with no return values 
(void):

public static void cancellingTrigger(TriggerData td) throws SQLException {
  if (td.getNew().getInt("num") < 0) {
    //Cancel operation - HOW???
  }
  else {
    //Continue
    //do something...
  }
}

Filip